Crane.



G. A. TRUE.

CRANE.

APPLICATION FILED NOV. 3, 1911.

1,017,824, Patented Feb. 20, 1912.

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COLUMBIA P'LANOGIAPH 50., WASHINGTON. D C- G. A. TRUE.

CRANE.

APPLICATION FILED NOV. 3, 1911.

1,017,824, Patented Feb.20, 1912.

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UNITED STATES PATENT OFFICE.

GEORGE A. TRUE, 0F DETROIT, MICHIGAN, ASSIGNOR 0F ONE-HALF T0 NORTHERNENGINEERING WORKS, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

CRANE.

To all whom it may concern:

Be it known that I, GEORGE A. TRUE, a cit-izen of the United States ofAmerica, residing at Detroit, in the county of Wayne and State ofMichigan, have invented certain new and useful Improvements in Cranes,of which the following is a specification, reference being had thereinto the accompanying drawings.

My invention relates to cranes and more particularly to the girders forthe traveling bridge.

The invention resides in the peculiar construction, arrangement andcombination of parts as more fully hereinafter described andparticularly pointed out in the claims.

In the drawings,-Figure l is a side elevation of a crane embodying myinvention; Fig. 2 is an end elevation; Fig. 3 is a side elevation of thebridge girder; Fig. i is a sectional perspective view; Figs. 5 and 6 aresections on the line wm and 3 3 respectively of Fig. 4; and Fig. 7 is aview similar to Fig. 5 showing a modified construction.

A represents the tracks for the bridge B, and O the trolley travelingupon tracks D on the bridge girders E. Necessarily the bridge girdersmust have considerable rigidity to withstand the enormous strainstransmitted thereto and also since the girders are of considerablelength it is desirable to reinforce the central or middle portion of thegirder. By my novel construction as herein-. after described, I providecomparatively light weight girders having the necessary strength. I havealso so arranged the girder parts as to prevent the trolley leaving thebridge in case the former is derailed.

As shown my improved girder comprises vertically disposed web plates Fand G and channel members H and I which are arranged between the webplates with their flanges positioned adjacent the margins of the webplates and riveted or otherwise secured thereto. The web plates havetheir lower marginal edges tapering from the center to the ends and thelower channel or chord member is correspondingly curved, producing ineffect a strut. The upper channel member which is straight and facedupward, supports the track rails D, the latter being secured to the baseof the channel so that the flanges form guards for the trolley wheels incase the trolley is derailed. Internal reinforcements are preferablypro- Specification of Letters Patent.

Patented Feb. 20, 1912.

Application filed November 3, 1911. Serial No. 658,295.

vided for the web plates and chord members such as the channel-shapedmembers J. These members have their flanges secured to the web plates byriveting and are of a length so that their ends abut against the upperand lower chord members.

The construction before described forms a box-shaped structurepossessing the requisite rigidity and strength and yet permits thegirder to be made of comparatively light weight metal. Furthermore, boththe web plates and channel members may be constructed from standardstock and by standard machinery which reduces the cost of manufacture toa mininrum.

The lower chord member may be so disposed that its flange portionsproject downward as shown in Fig. 6 or upward as in Fig. 7, since thebending of the lower chord member so that it will conform to the contourof the lower marginal edges of the web plates may as readily be eifectedin either arrangement.

What I claim as my invention is,

1. In a crane, a bridge girder comprising spaced vertically disposed webplates having their lower marginal edges tapering for a portion of theirlength to the ends, and top and bottom chord plates in the form ofchannel irons arranged between the web plates and having their flangespositioned intermediate the web plates and secured thereto, the lowerchannel being bent to conform to the lower marginal edges of the webplates.

2. In a crane, a bridge girder comprising spaced vertically disposed webplates having their lower marginal edges tapering for a portion of theirlength to the ends, and top and bottom chord plates in the form ofchannel irons arranged between the web plates and having their flangespositioned intermediate the web plates and secured thereto, the lowerchannel being bent to conform to the lower marginal edges of the webplates and the upper channel being substantially straight, and a trolleyrail supported upon the base of the upper channel, the latter beingfaced upward, whereby the flanges thereof form guards for the purposedescribed.

3. In a crane, a bridge girder comprising spaced vertically disposed webplates having their lower marginal edges tapering for a portion of theirlength to the ends, and top and bottom chord plates formed of channelirons arranged between the web plates and having their flanges securedthereto, the lower channel being bent to conform to the lower marginaledges'of the web plates, and an internal reinforcement for said webplates.

4:. In a crane, a bridge girder comprising spaced vertically disposedweb plates having their lower marginal edges tapering for a portion oftheir length to the ends and top, and bottom chord plates formed ofchannel irons arranged between the web plates and having their flangessecured thereto, the lower channel being bent to conform to the lowermarginal edges of the web plates, and a vertically ar 'anged channelreinforcing member for the chord members and web plates positionedintermediate the latter and having their flanges secured thereto, and

a plurality of spaced internal. reinforcements for the chord members andweb plates.

In testimony whereof I afliX my signature in presence of two witnesses.

GEORGE A. TRUE.

Witnesses LoUIs H. OLrs, lV. G. CHnsnBRoUoH.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

